1. Field of the Invention
The present invention relates to a hole-piercing punch for piercing holes in paper sheets such as papers and sheets and particularly relates to an energy-saving configuration for reducing the hole-piercing load.
2. Description of the Related Art
A hole-piercing punch has been proposed for reducing the hole-piercing load. The hole-piercing punch has a base platform, support platform, handle, punching member, and the like. For example, for reducing the hole-piercing load, there is a hole-piercing punch with a handle (handling member) that is formed with maximum length. This handle is formed by being extended in the direction protruding from the base platform of the hole-piercing punch and is for applying a load on the punching member by which hole-piercing is carried out.
Furthermore, the following are other examples of hole-piercing punches to reduce the hole-piercing load. For example, the end opposite the end of a base platform side of a handle when carrying out hole-piercing with a hole-piercing punch is resumed to be a power point, and the pivoting shaft of the handle is a fulcrum. Furthermore, the punching member is an action point. Such a hole-piercing punch is formed so that the distance between the action point and the fulcrum becomes short and also the angle formed by the handle and the base platform becomes wide. With such a hole-piercing punch, increasing the force for acting on the action point may decrease the hole-piercing load.
Furthermore, another example of a hole-piercing punch for reducing the hole-piercing load is as follows. For example, there is a hole-piercing punch with a shifting fulcrum (hereinafter referred to as a “fulcrum-shifting punch”) and a hole-piercing punch with a fixed fulcrum (hereinafter referred to as a “fulcrum-fixed punch”). It should be noted that “shifting fulcrum” means that the position of the pivoting shaft of the handle with respect to the support platform on the base platform is shifted, and “fixed fulcrum” means that the positional relation of the support platform and the pivoting shaft of the handle is approximately fixed.
Hereafter, the outline of a fulcrum-shifting punch is described using FIG. 1. FIG. 1A is a lateral view of a conventional fulcrum-shifting punch 200 when a punching member 211 starts descent. FIG. 1B is a lateral view of a conventional fulcrum-shifting punch 200 when finishing hole-piercing.
As shown in FIG. 1, a fulcrum-shifting punch 200 has a support platform 204 fixed onto the top surface of a base 202 by a securing fixture 203. The support platform 204 supports a handle 207 and a punching member 211. At one end of the support platform 204, a support shaft-guiding hole 205, having a longitudinal direction in the direction substantially orthogonal to the top surface of the base 202. Furthermore, at the other end of the support platform 204, a pivoting shaft-guiding groove 206, having a longitudinal direction in the direction substantially parallel to the top surface of the base 202.
Moreover, as shown in FIG. 1, at one end of the base 202 side of the handle 207, round hole 208 and round hole 209 are provided. The handle 207 is pivotably mounted onto the support platform 204 by inserting a pivoting shaft 210 into round hole 208 and the pivoting shaft-guiding groove 206 of the support platform 204. Furthermore, a support shaft 212 comprising a punching member 211 that extends in the same direction as the support shaft-guiding hole 205 is inserted into round hole 209 of the handle 207 and the support shaft-guiding hole 205 of the support platform 204 so as to be parallel to the top surface of the base 202.
Piercing of a hole in sheet materials such as paper sheets using the fulcrum-shifting punch 200 is performed by a user as follows. First, as shown in FIG. 1A, when the tip (blade part) of the punching member 211 is away from the top surface of the base 202 while no force is being applied to the handle 207 (power point) of the fulcrum-shifting punch 200, the user inserts paper sheets into the space 213 between the top surface of the base 202 and the support platform 204.
After the paper sheets are inserted by the user, the user presses down the handle 207 as shown in FIG. 1B. As a result of having been pressed down by the user, the handle 207 is pivoted with the pivoting shaft 210 acting as the fulcrum. The direction of the handle 207 to be pivoted by the user is the direction in which the tip of the handle 207 approaches the top surface of the base 202 (X1 direction in FIG. 1B).
When the handle 207 is pressed down, the support shaft 212 attached to the punching member 211 and inserted into round hole 209 shifts by being guided by the support shaft-guiding hole 205 of the support platform 204. The shifting direction of the support shaft 212 is the direction toward the top surface of the base 202 (Y1 direction in FIG. 1B). When the support shaft 212 shifts in the direction toward the top surface of the base 202, the punching member 211 pierces holes in the paper sheets that have been inserted into the space 213.
In a fulcrum-shifting hole-piercing punch such as the one described above, the manual force acts on the support shaft 212 via round hole 209 when the handle 207 is pivoted by the user. The support shaft 212 is guided by the support shaft-guiding hole 205 for a reciprocal linear movement in a direction orthogonal to the top surface of the base 202. As a result of the movement (downward) of the support shaft 212 in a direction orthogonal to the top surface of the base 202, the punching member 211 makes a hole-piercing movement into the paper sheets. Then, the support shaft 212 is controlled by the support shaft-guiding hole 205 in a direction that is parallel to the top surface of the base 202 (Z1 direction in FIG. 1B) and is not pivoted with the pivoting of the handle 207.
Furthermore, when the punching member 211 makes the hole-piercing movement into the paper sheets, guided by the pivoting shaft-guiding groove 206 provided in the support platform 204, the pivoting shaft 210 moves in a direction parallel to the top surface of the base 202 (Z1 direction in FIG. 1B) so as to move away from the support shaft 212 (the amount of movement is represented as t).
In general, with a hole-piercing punch, at the moment when the paper sheets begin to be pierced by a hole, the maximum hole-piercing load as the load required for hole piercing (hereinafter, simply referred to as “maximum hole-piercing load”) is supposed to be applied. Furthermore, as shown in FIG. 1B, when the maximum hole-piercing load is applied to the fulcrum-shifting punch 200, the distance L2a′ between the axial centers of the pivoting shaft 210 and the support shaft 212 changes as described below. Specifically, when the maximum hole-piercing load is applied to the fulcrum-shifting punch 200, the support shaft 212 moves from one end of the support shaft-guiding hole 205 to the center, and the pivoting shaft 210 also moves from one end of the support shaft-guiding hole 205 side in the pivoting shaft-guiding groove 206 to the other end. Then, the pivoting shaft 210 moves away from the punching member 211 by an amount equivalent to the amount of movement t. Once the pivoting shaft 210 moves as described when the maximum hole-piercing load is applied to the fulcrum-shifting punch 200, the distance L2a′ between the fulcrum (pivoting shaft 210) and the action point (support shaft 212) becomes greater in comparison to the distance L2a (FIG. 1A) at the time when the punching member 211 begins to descend.
When calculated in terms of the principle of leverage, at a time when the maximum hole-piercing load is applied to the handle 207 of the conventional fulcrum-shifting punch 200, that is, the load to be applied to the tip of the handle 207 is described as below.